A digital computer system executes programs each comprising a plurality of sequentially-processed instructions which indicate how information, including commands and data, are to be processed. During execution of a program, the computer system generally processes data which is provided by a number of sources, which may be identified as objects, such as disk files in which previously-acquired data is stored in the computer system, and also externally-provided data which may be obtained from remote sources over, for example, networks and telecommunications lines, as well as from the operator.
In executing a program, the computer system may also use commands received from an operator through, for example, a video display terminal to control execution at particular points in execution of the program. A command enables the computer system to sequence to a particular portion of the program instructions, enabling the computer to perform selected operations at that point. The program is thus interactive, that is, the operator can control execution of the program while the program is in execution. For a number of programs, command syntax can be quite involved, including a number of parameters and arguments. To simplify entry of commands and particularly command sequences which an operator may use often, many programs provide a "macro" facility, which enables the operator, while executing a program, to record commands and command sequences and associate each command or sequence with a series of characters or keystrokes, termed a "macro," which may be easily entered. When the operator enters a series of characters or keystrokes, the computer system, enabled by the program, determines whether they correspond to a previously-entered macro, and if so, it executes the commands associated with the macro.
During a particular processing session, an operator may need to use a plurality of programs sequentially to perform a particular processing operation. To accomplish this, the operator typically calls and uses each program until finished, exiting each program before calling another program. This process may proceed through a number of programs until the processing operation has been completed. Typically, programs have diverse calling syntaxes, that is, arguments and parameters that are used in calling the programs, as well as diverse command syntaxes, and so the process of calling the programs, as well as entering the commands therefor, during a session can often be quite laborious and prone to error.